What is the best bait to trap a rat?

It doesn’t really matter what bait you use to trap a rat. They’re
scavengers, and they’ll generally go for anything you put down. They’re
omnivores, which means they eat both plant and meat matter, so you could
use leftover dinners, pet food, anything you like. Sweet treats seem to
do the best job of catching them, but different people have had
different results. The art is getting the trap placement just right. If
you don't do that, you won't have any luck at all, regardless of what
bait you choose to put down.

The traps will need to be placed in areas that the rats visit the most
often, and there’s a clever trick for working out where those areas are.
Flour or icing sugar - a white powder (that preferably won’t kill the
rats) placed on the floor of the places you think they’re having a party
when your'e not looking. If you're right, the flour will be dislodged by
their teeny-tiny feet, and you’ll see lots of little rat-prints. Those
are the areas in which you should place the traps, because you have the
biggest chance of success. If you put the traps where the rat doesn't
visit, there's a good chance it won't ever visit there. That means your
bait will be pointless, and the trap itself won't ever get used.

We don’t advise using traps to catch and remove rats, but if you have
decided to take this action, make sure you check them regularly. You
really won’t want to leave food going bad just left around your home.
You also don’t want to leave a dead rat lying around, especially if
you've used poison as well. We hope you haven’t, as it’s not the
greatest method you could have chosen, but you certainly don't want your
cat to become ill form accidentally ingesting the rat that you have
poisoned.